Cleaning apparatus for automobiles with indirect heat exchange for heating the cleaning fluid

ABSTRACT

A cleaning apparatus for heating water and for delivering it at a substantially constant temperature. A pump circulates an intermediate or heat-transfer liquid through a first heatexchange coil and an annular chamber. A burner heats the first heat-exchange coil, which delivers the hot heat-transfer liquid to the chamber with a swirling motion. The water to be heated is sent through a second heat-exchange coil in the annular chamber where it is heated by the heat-exchange liquid, giving a very good control for maintaining even temperatures. Detergent may then be injected, if desired, into the hot water.

United States Patent 1191 Machado Jan. 115, 1974 [54] CLEANING APPARATUS FOR 3,522,909 8/1970 Arant 122 33 x AUTOMOBILES WITH INDIRECT HEAT 2,860,917 11/1958 Thompson 126/344 X 2,904,014 9/1959 Meyers 122/33 EXCHANGE FOR HEATING THE 2,632,672 3/1953 Waterman 137/94 x CLEANING FLUID Joseph G. Machado, 3447 Railroad Ave., Ceres, Calif. 95307 Filed: Apr. 7, 1972 Appl. No.: 242,096

Related US. Application Data Continuation-impart of Scr. No. 88,818, Nov. 12, 1970, abandoned.

lnventor:

References Cited UNITED STATES PATENTS 8/1968 Zangl 122/33 7/1954 Karlen 122/33 X Primary ExaminerWilliam F. ODea Assistant ExaminerWilliam C. Anderson Attorney-Robert E. Wickersham et a1.

[57] ABSTRACT A cleaning apparatus for heating water and for delivering it at a substantially constant temperature. A pump circulates an intermediate or heat-transfer liquid through a first heat-exchange coil and an annular chamber. A burner heats the first heat-exchange coil, which delivers the hot heat-transfer liquid to the chamber with a swirling motion. The water to be heated is sent through a second heat-exchange coil in the annular chamber where it is heated by the heatexchange liquid, giving a very good control for maintaining even temperatures. Detergent may then be injected, if desired, into the hot water.

7 Claims, 5 Drawing Figures PATENIEDJANWQH 3.785863 SHEET 2 0F 3 FIG. 2

PMENTED JAN I 5|974 SHEET 3 BF 3 1 CLEANING APPARATUS FOR AUTOMOBILES WITH INDIRECT HEAT EXCHANGE FOR HEATING THE CLEANING FLUID CROSS-REFERENCE TO A RELATED APPLICATION This application is a continuation-in-part of application Ser. No. 88,818, filed Nov. 12, 1970 and now abandoned.

BACKGROUND OF THE INVENTION 7 This invention relates to an improved apparatus for cleaning things such as automobiles and equipment with hot water, with or without detergent.

In cleaning automobiles efficiently, especially using automatic machinery, a good supply of very hot water is needed, both for applying a detergent solution and for rinsing. Such hot water should be kept very close to a set perdetermined temperature, so that consistent results can be obtained within a brief perdetermined time. The temperature should not vary according to the amount of water used, nor should heat be wasted.

Heat exchangers are, of course, well known, and it is common to have a heat-exchange coil heated by a gas burner or electrical heater. However, many such heat exchangers tend to be somewhat erratic, due to fluctuation of the heat supplied by the burner or the electric current. The fluid is heated but it is not heated at a constant rate or to a constant temperature.

Control of temperature is important not only during ordinary conditions but also when abnormal conditions obtain e.g., when the circulating pump fails to operate, so that continued heating would become dangerous. Ties between fluid flow and the heating flame are important, as are by-pass arrangements. Efficiency and safety are both needed.

BRIEF SUMMARY OF THE INVENTION The present invention is designed to heat the cleaning fluid water or an aqueous detergent solution, typically to an even temperature by means of an indirect heat exchange between a heater and the cleaning fluid, through the intermediation of an additional liquid which is itself heated by the burner and then is used to heat the output fluid.

The heater, such as a gas burner, is contained in a heater housing, and above the burner is supported a first heat-exchange coil. The intermediate liquid is circulated from a pump through this heat-exchange coil and then is set back to the pump by swirling it through an annular chamber that surrounds the heater housing and is preferably insulated from outside. The output or cleaning fluid is heated by passing it through a second helical heat-exchange coil that is supported in the annular chamber and is therefore not subject to direct contact by the flame at any time, but this coil is in contact with the intermediate liquid which has been heated by the flame.

A switch actuated by the actual flow of the intermediate liquid from the circulating pump to the first heatexchange coil controls the flow of gas to the burner and thereby turns the burner off if the intermediate liquid is not flowing. Thermostats actuated by the temperature of the intermediate liquid just after it passes from the first heat-exchange coil into the annular chamber, regulate the burner and therefore the temperature of the heat exchange liquid, so that the temperature of the cleaning liquid remains constant at the outlet from the second heat-exchange coil.

The annular chamber, first heat-exchange coil, and pump comprise a sealed system, and the liquid therein is kept under pressure to enhance efficiency, with a pressure relief valve to prevent excessive pressures and ensure safety. Tangential entry and outflow of the intermediate liquid assure a swirling generally helical flow of liquid that surrounds all the outer surface of the second heat-exchange coil and heat it very efficiently in a counter current flow.

Other objects and advantages of the invention will appear from the following description of a preferred form thereof.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a top plan view of an apparatus embodying the principles of the invention, with some portions broken off and some portions shown in section.

FIG. 2 is a view in side elevation and partially in section of the apparatus in FIG. 1, taken generally along the line 22 in FIG. 1.

FIG. 3 is an enlarged view in section taken along the line 3-3 in FIG. 1 showing the heat-exchanger portion of the apparatus.

FIG. 4 is an enlarged fragmentary view in section taken along the line 4-4 in FIG. ll.

FIG. 5 is a fragmentary view in section taken along the line 5-5 in FIG. 3.

DESCRIPTION OF A PREFERRED EMBODIMENT In a preferred embodiment, cold tap water from an inlet conduit 10 enters a float tank 11 (see FIGS. 1 and 2) where a float valve 12 provides a constant head. A conduit 13 leads from the bottom of the float tank 11 to a high-pressure pump 14 that is driven by a motor 15 through a belt drive 16. Water leaves the pump 14 via a conduit 17 and a pressure relief valve 17a which is connected to a surge tank 18, and flows via a conduit 19 to a heat exchanger 20. The pressure-relief valve may recirculate some water to the float tank 11 via a conduit 19a.

The heat-exchanger 20 (see FIG. 3, especially) preferably having a cylindrical wall 21 may be supported by suitable legs 22, and it supports a suitable heating means such as a gas burner 23. In place of the gas burner, some ,other type of heating means may be used if desired, but a gas burner is generally the most efficient and most useful for this kind of operation. Above the burner 23, the wall 21 is provided with an inwardly extending annular ledge 24, which supports a first heatexchange coil 25. Various types of heat-exchange coils may be used, and the invention is not confined to the use of any particular type. For an example, a finned copper tubing has been shown, and the tube 25 is coiled as a double cone because that is one efficient type of structure, but other kinds can, of course, be used. The coil 25 as shown, thus, has outer fins 26 of copper, which conduct the heat into the tube itself. The coil 25 has an outlet 27 at the top and an inlet 28 at its lower end. At the top of the heater there is a cover 29 having an exhaust opening 39, to which a duct may be connected.

Surrounding the wall 21 and concentric with it, is a wall 30, providing an annular chamber 31 between the wall 30 and the wall 21. Preferably, a layer of insulation 32 surrounds the wall 30 to help prevent dissipation of the heat to the atmosphere. The chamber 31 is sealed by top and bottom walls 33 and 34 to enable the development of pressure. To enable the adding of heat transfer liquid to the system and to the annular chamber 31, there may be an inlet spout 35, extending outwardly from one portion of the wall 30 and having a sealing cap 36 which is normally kept tight but has a pressure relief valve 37 therein to prevent too high a pressure build-up e.g., higher than 7.5 p.s.i. The chamber 31 is not filled all the way to the top, and its unfilled upper end serves as an expansion space, so that there is no need for a separate expansion tank.

The interior of the heat-exchange tube 25 leads into the chamber 31 by means of the tube 27 and. an opening 38, which causes tangential inflow of the liquid from the coil 25 into the chamber 31. This tangential entry induces a swirl, so that the liquid 40 flows in a generally helical path around the chamber 31, gradually flowing down toward an outlet 41 perpendicular to the flow, near the bottom wall 34.

A circulating pump 42 is provided having an outlet conduit 43 connected by suitable tubing 44 to the inlet 28 of the coil 25. A flow-sensitive member 45 is actuated by a predetermined minimum flow of liquid through the conduit 43 and itself activates a switch 46 that governs the flow of gas to the burner 23, cutting off the gas if there is no flow of the intermediate liquid 40 or if the predetermined minimum flow is not exceeded. The input to the pump 42 comes from a conduit 47 from the chamber outlet 41. There may be drain plug 48 for draining the liquid from the chamber 31 when that is desired, as for replacing it with new liquid.

The intermediate or heat-exchange liquid 40 in the chamber 31 and coil 25 may be any desired liquid, such as water, or water containing anti-freeze, or water containing anti-rusting agents, or it may be oil, or alcohol, and so on. Usually it is preferred that most of it be water or an aqueous solution because water is the most efficient heat-exchange material. All entries into the chamber 21 are sealed, and the sealed system is normally used to heat the liquid 40 under pressure.

In the present invention indirect heat exchange is obtained by the use of a second heat-exchange coil 50. This coil 50 is connected to the water pipe 19 and may have a lower bare portion 51 and an upper portion 52 of the finned tubing, with fins 53. However, this is not essential to the invention and it may in some forms be desirable to have it uniform and either have it all finned or all plain. The important thing, here, is that this second coil 50 lies inside chamber 31, where (at most) it occupies only about half of the width of the chamber 31, so that it is in exchange with the liquid 40 on all sides and obtains its heat therefrom and does not obtain any heat directly from the burner 23. The contact of the tube 50 with the liquid 40 for its full circumference helps the efficiency, as does the fact that the water in the tube 50 is moving countercurrently with respect to the liquid in the chamber 31. The liquid 40 in the chamber 31 is hottest at the top, and the water in the coil 50 leaves the exchanger 20 at about the same temperature as that hot liquid 40. The heat exchanger coil 50 may have an inlet 54 connected to a supply of the desired fluid in the conduit 19, and an outlet 55 for the heated fluid. Again, the fluid 56 in the coil 50 may be any fluid, either a gas or a liquid of any kind, whatever is desired to be heated. In most instances, it is water; it may even be identical to the heat-transfer liquid used in the first heat-exchange coil 25, but it will have the advantage that its temperature is kept at a very uniform level, by virtue of the indirect heat exchange. it may, of course, be quite a different liquid. The flow of the water or other liquid from the outlet may be started or stopped at any time without changing the temperature. This becomes very important when the outlet supplies steam to a steam cleaner, for example.

Since the second heat-exchange coil 50 is not heated by the direct flame from the burner, which normally causes a build-up of scale in such a coil, the invention minimizes scaling from hard water and detergents. The heat-exchange liquid 40 can be free from scale-causing chemicals. By preventing the formation of scale deposits, the invention prevents the decrease in the efficiency of heat transfer which results when there is such scaling and which eventually even results in plugging the coil. The heat-transfer liquid 40 in the first coil 25 and in the annular chamber 31 can be used indefinitely, being the same liquid recycled, and never results in plugging or even in a decrease in heat-transfer efficiency.

A thermometer 57 indicates the temperature of the water coming from the outlet 55. This temperature is regulated mainly by two thermostats 58 and 59 a regular thermostat 58 which turns the gas off at a predetermined upper temperature (e.g., 210 F.) and turns the gas on again when it drops below a predetermined lower temperature (e.g., 205 F.), and a safety thermostat 59 which at a selected critical temperature (e.g., 220 F.) indicating that something is wrong with the thermostat 58, turn the burner 23 off completely. A second thermometer 60 shows the temperature of the heat exchange liquid 40 at the top of the chamber 31.

The burner 23 has a pilot light (not shown) enabling the burner 23 to be turned on and off as controlled by the thermostats 58 and 59 and by the flow switch 45. There is a main switch 61 connected by a lead 62 to an on-off gas flow valve 63. A lead line 64 from the switch 46 goes to the lead 62 and thence to the valve 63 to shut off the gas from a conduit 67. The thermostats 58 and 59 also are tied to the valve 63 via lines 64, 65 and 66 and 62.

A system for adding either of two kinds or strengths of detergents to the hot water comprises a tank 70 for one (e.g., normal strength) detergent for washing automobile bodies and a tank 71 for a stronger detergent for washing other types of equipment requiring stronger detergents, degreasers, acidic or caustic solutions. A valve 72 enables selection between the detergent coming via a conduit 73 from the tank 70 and the detergent coming via a conduit 74 from the tank 71, passing the selected detergent into a conduit 75. The selected detergent solution in either event quite concentrated passes via a check valve 76 to a detergent injector 77 operated by the pump 14 and thence flows via a second check valve 78 to a metering valve 79, which can be turned by the operator to regulate the amount of detergent or other chemical that is injected into the hot water conduit, preferably at a tee 80 connected to a conduit 81 downstream of the heat exchange coil 50 and just ahead of a hose 82 or other conduit which carries the hot liquid or solution to items that are to be cleaned or washed. Note also that cold water may be by-passed via a conduit 83 to the conduit 81. A tee 84 is used, and a hot water valve 85 and a cold water valve 86 are used for control, mixture, or by-passing.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

I claim:

1. A cleaning device, including in combination:

an upright cylindrical heat exchanger housing,

heating means in said housing,

first heat-exchange means for liquid, in said housing and heated by said heating means, said heatexchange means having an inlet and an outlet,

a cylindrical wall surrounding said housing and spaced outwardly therefrom and defining between itself and said housing an annular chamber; said outlet of said heat-exchange means leading tangentially into an upper portion of said chamber lying below the upper end thereof to provide a liquidfree expansion space thereabove, said chamber having an outlet conduit near its lower end lying athwart the path of flow of said liquid around said annular chamber,

circulating pump means having an inlet connected to said outlet conduit from said chamber and an outlet connected to the inlet of said first heatexchange means,

upper and lower closure means connected to said wall and to said housing for sealing said chamber, whereby said pump can circulate liquid in a sealed system from the outlet of said first heat-exchange means into said chamber tangentially, swirling in said chamber in a downward helical path to said outlet conduit and back from there through the pump to the inlet of said first heat-exchange means in a continuous cycle,

pressure relief means for said closed system in said upper closure means at the upper end of said expansion space to prevent too high a pressure buildup, and

second heat-exchange means for a fluid to be heated and comprising, a helical coil in said annular chamber substantially narrower than said chamber so that its full circumference is in contact with said helically downwardly swirling liquid, and having an inlet end at the lower end of said chamber and an outlet end located at the upper end of said chamber, for heat exchange between said liquid and said fluid,

whereby said fluid is heated by the heat imparted to said second heat-exchange means by countercurrent flow of said liquid rather than being directly heated by said heating means, thereby giving improved control of the temperatures imparted to said fluid.

2. The device of claim 1 having flow-sensitive means in the circulation path of said liquid for turning off said heating means when the flow of said liquid drops below a predetermined value.

3. The device of claim 1 having means for injecting detergent into said fluid after it passes said outlet end and for doing so at any of various rates.

4-. The device of claim 1 having by-pass means for passing said fluid around said second heat-exchange means and valve means for mixing by-passed said fluid with heated said fluid.

5. A cleaning device, including in combination:

an upright cylindrical housing having a lower end and an upper end,

a gas burner in and at the lower end of said housing,

a first heat-exchange coil for the flow of liquid therethrough, located in an upper portion of said housing and heated directly by said burner, said coil having an inlet at a lower end thereof and an outlet at an upper end thereof,

an insulated cylindrical wall surrounding said housing, concentric therewith and spaced outwardly therefrom and defining between itself and said housing an annular chamber, said coil outlet being connected to said chamber through a sealed tangential opening at the upper end of said chamber inducing circular flow of said liquid in said chamber, said annular chamber having an outlet conduit with a radially extending opening lying near the bottom of said chamber, so that said liquid swirls helically downward in said chamber from said tangential opening to said radially extending opening,

top and bottom walls joining said cylindrical wall and said housing and sealing said annular chamber, while leaving a central exhaust opening for the burned gas from said burner, said top wall being spaced above said tangential opening to provide an expansion space,

a circulating pump having an outlet connected to the inlet of said first heat-exchange coil and an inlet connected to said outlet conduit from said chamber, whereby said liquid is circulated by said pump in a closed, pressurized system into said coil inlet, through said coil outlet to said chamber and back from there to said pump in continuous cycle, and

a second heat-exchange coil for a fluid to be heated,

having an inlet end at the lower end of said chamber and an outlet end at the upper end of said chamber and located entirely in said chamber spaced from the walls-thereof and only about half as wide as said chamber, for full circumference heat exchange between said liquid and said fluid,

whereby said fluid is heated by the heat imparted to said second coil by countercurrent flow of said liquid rather than being directly heated by said burner, thereby giving improved control of the temperatures imparted to said fluid.

6. The device of claim 5 having means for injecting a chemical solution into said fluid beyond said outlet end.

7. The device of claim 5 having flow-sensitive means in the circulatory path of said liquid for turning off the gas to said burner when the liquid fails to circulate properly. 

1. A cleaning device, including in combination: an upright cylindrical heat exchanger housing, heating means in said housing, first heat-exchange means for liquid, in said housing and heated by said heating means, said heat-exchange means having an inlet and an outlet, a cylindrical wall surrounding said housing and spaced outwardly therefrom and defining between itself and said housing an annular chamber; said outlet of said heat-exchange means leading tangentially into an upper portion of said chamber lying below the upper end thereof to provide a liquid-free expansion space thereabove, said chamber having an outlet conduit near its lower end lying athwart the path of flow of said liquid around said annular chambeR, circulating pump means having an inlet connected to said outlet conduit from said chamber and an outlet connected to the inlet of said first heat-exchange means, upper and lower closure means connected to said wall and to said housing for sealing said chamber, whereby said pump can circulate liquid in a sealed system from the outlet of said first heat-exchange means into said chamber tangentially, swirling in said chamber in a downward helical path to said outlet conduit and back from there through the pump to the inlet of said first heat-exchange means in a continuous cycle, pressure relief means for said closed system in said upper closure means at the upper end of said expansion space to prevent too high a pressure buildup, and second heat-exchange means for a fluid to be heated and comprising, a helical coil in said annular chamber substantially narrower than said chamber so that its full circumference is in contact with said helically downwardly swirling liquid, and having an inlet end at the lower end of said chamber and an outlet end located at the upper end of said chamber, for heat exchange between said liquid and said fluid, whereby said fluid is heated by the heat imparted to said second heat-exchange means by countercurrent flow of said liquid rather than being directly heated by said heating means, thereby giving improved control of the temperatures imparted to said fluid.
 2. The device of claim 1 having flow-sensitive means in the circulation path of said liquid for turning off said heating means when the flow of said liquid drops below a predetermined value.
 3. The device of claim 1 having means for injecting detergent into said fluid after it passes said outlet end and for doing so at any of various rates.
 4. The device of claim 1 having by-pass means for passing said fluid around said second heat-exchange means and valve means for mixing by-passed said fluid with heated said fluid.
 5. A cleaning device, including in combination: an upright cylindrical housing having a lower end and an upper end, a gas burner in and at the lower end of said housing, a first heat-exchange coil for the flow of liquid therethrough, located in an upper portion of said housing and heated directly by said burner, said coil having an inlet at a lower end thereof and an outlet at an upper end thereof, an insulated cylindrical wall surrounding said housing, concentric therewith and spaced outwardly therefrom and defining between itself and said housing an annular chamber, said coil outlet being connected to said chamber through a sealed tangential opening at the upper end of said chamber inducing circular flow of said liquid in said chamber, said annular chamber having an outlet conduit with a radially extending opening lying near the bottom of said chamber, so that said liquid swirls helically downward in said chamber from said tangential opening to said radially extending opening, top and bottom walls joining said cylindrical wall and said housing and sealing said annular chamber, while leaving a central exhaust opening for the burned gas from said burner, said top wall being spaced above said tangential opening to provide an expansion space, a circulating pump having an outlet connected to the inlet of said first heat-exchange coil and an inlet connected to said outlet conduit from said chamber, whereby said liquid is circulated by said pump in a closed, pressurized system into said coil inlet, through said coil outlet to said chamber and back from there to said pump in continuous cycle, and a second heat-exchange coil for a fluid to be heated, having an inlet end at the lower end of said chamber and an outlet end at the upper end of said chamber and located entirely in said chamber spaced from the walls thereof and only about half as wide as said chamber, for full circumference heat exchange between said liquid and said fluid, whereby said fluid is heated by the heat imparted to said second coil by countercurrent flOw of said liquid rather than being directly heated by said burner, thereby giving improved control of the temperatures imparted to said fluid.
 6. The device of claim 5 having means for injecting a chemical solution into said fluid beyond said outlet end.
 7. The device of claim 5 having flow-sensitive means in the circulatory path of said liquid for turning off the gas to said burner when the liquid fails to circulate properly. 